Figure 4.1 Clumped, random, and uniform distributionEcological Niches
An ecological niche is the particular area within a habitat occupied by an
organism and includes the function of that organism within an ecological
community. The physical environment influences how organisms affect and are
affected by resources and competitors. The niche reflects the specific adaptations
that a species has acquired through evolution. To describe an organism’s niche
involves a description of the organism’s adaptive traits, habitat, and place in the
food web. A niche also takes into account the types and amounts of resources the
species uses and its interactions with both living (biotic) and nonliving (abiotic)
factors in its habitat.
Generalist species live in broad niches. They are able to withstand a wide
range of environmental conditions. Examples of generalist species include
cockroaches, mice, and humans. Specialist species live in narrow niches and are
sensitive to environmental changes. Since they cannot tolerate change, they are
more prone to extinction. An example of a specialist species is the giant panda,
which only eats a certain type of bamboo. When environmental conditions are
stable, specialist species have an advantage since there are few competitors as
each species occupies its own unique niche (competitive exclusion principle).
However, when habitats are subjected to rapid changes, the generalist species
usually fare better since they are more adaptable.
Ecosystem Services
Humankind benefits from ecosystems in a multitude of ways. Collectively, these
benefits are known as ecosystem, or ecological, services. Ecosystem services can
be grouped into four broad categories: ■ Provisioning (e.g., production of food
and water)
■ Regulating (e.g., control of climate and disease)